Function handler_apply 

pub const fn handler_apply(row: EffectRow, handler: Handler) -> EffectRow

Apply handler to row and return the residual row of open effects.

Algebraic identity: handler_apply(handler_apply(row, h), h) == handler_apply(row, h) (idempotent), and handler_apply(row, Handler::from_row(EffectRow::empty())) == row (identity handler).